Novak Djokovic remains capable of enjoying a successful 2024 but has been declining for some time, believes former world number six Gilles Simon.

Djokovic won three grand slam singles titles last year to take his overall tally to 24, equalling Margaret Court's overall record among male and female players.

However, he has been far from his best in 2024, going out to eventual winner Jannik Sinner in the Australian Open semi-finals and failing to capture a single ATP Tour title.

Djokovic was beaten by Tomas Machac in the last four at the Geneva Open last week and said on Monday he was "not expecting" to retain his French Open crown.

He begins his Roland-Garros campaign against Pierre-Hugues Herbert on Tuesday.

Speaking to Stats Perform at the Roland-Garros eSeries by Renault tournament, Simon feels Djokovic's downturn is only natural, given he turned 37 earlier this month.

Simon said: "You are in a very short media window and it is amazing how things change. Last year when he lost [the Wimbledon final to Carlos Alcaraz], I said that for me, he had one year left.

"It's more a question of age, there's a break around 37 or 38, when it gets tough. He was playing well last year, he won three grand slams, but I've seen him drop for a while now.

"For me, there were already signs on the court that he's dropping, but he was and still is completely capable of having a great 2024 season. 

"I have more doubts about the 2025 season, and I already had some last year, above all linked to the physical aspect."

Despite a difficult few months, Simon has no doubt that Djokovic – who is 14-5 for 2024 – can still put himself in contention for silverware. 

"Now he's in a slump, so everyone wants to bury him, but he's still capable of playing very well," he continued. 

"Last year it was [seen as] shameful to say that he was starting to drop, with people saying, 'You're talking rubbish, he's won three grand slams'.

"If I say now that he's playing well, they'll tell me he's finished, that he lost again in Geneva. Take it easy! We're not going to bury him. Nobody's going to bury Novak and he is still capable of great things.

"On the other hand, he's like everyone else. He's reaching an age where players like [Rafael] Nadal before him or like [Roger] Federer before him have dropped."